1. Field of the Invention
The present invention pertains to the field of soft tissue excisional biopsy devices and methods. In particular, the present invention relates to the field of devices and methods for excising suspicious lesions from soft tissue, such as breast tissue.
2. Description of the Related Art
Breast cancer is a major threat and concern to women. Early detection and treatment of suspicious or cancerous lesions in the breast has been shown to improve long term survival of the patient. The trend is, therefore, to encourage women not only to perform monthly self-breast examination and obtain a yearly breast examination by a qualified physician, but also to undergo annual screening mammography commencing at age 40. Mammography is the only screening modality available today that can detect small, nonpalpable lesions. These nonpalpable lesions may appear as opaque densities relative to normal breast parenchyma and fat or as clusters of microcalcifications.
The conventional method for diagnosing, localizing and excising nonpalpable lesions detected by mammography generally involves a time-consuming, multi-step process. First, the patient goes to the radiology department where the radiologist finds and localizes the lesion either using mammography or ultrasound guidance. Once localized, a radio-opaque wire is inserted into the breast. The distal end of the wire may include a small hook or loop. Ideally, this is placed adjacent to the suspicious area to be biopsied. The patient is then transported to the operating room. Under general or local anesthesia, the surgeon performs a procedure called a needle-localized breast biopsy. In the needle-localized breast biopsy, the surgeon, guided by the wire previously placed in the patient""s breast, excises a mass of tissue around the distal end of the wire. The specimen is sent to the radiology department where a specimen radiograph is taken to confirm that the suspicious lesion is contained within the excised specimen. Meanwhile, the surgeon, patient, anesthesiologist and operating room staff, wait in the operating room for confirmation of that fact from the radiologist before the operation is completed. The suspicious lesion should ideally be excised in toto with a small margin or rim of normal breast tissue on all sides. Obtaining good margins of normal tissue is extremely dependent upon the skill and experience of the surgeon, and often an excessively large amount of normal breast tissue is removed to ensure that the lesion is located within the specimen. This increases the risk of post-operative complications, including bleeding and permanent breast deformity. As 80% of breast biopsies today are benign, many women unnecessarily suffer from permanent scarring and deformity from such benign breast biopsies.
More recently, less invasive techniques have been developed to sample or biopsy the suspicious lesions to obtain a histological diagnosis. The simplest of the newer techniques is to attempt visualization of the lesion by external ultrasound. If seen by external ultrasound, the lesion can be biopsied while being continuously visualized. This technique allows the physician to see the biopsy needle as it actually enters the lesion, thus ensuring that the correct area is sampled. Current sampling systems for use with external ultrasound guidance include a fine needle aspirate, core needle biopsy or vacuum-assisted biopsy devices.
Another conventional technique localizes the suspicious lesion using stereotactic digital mammography. The patient is placed prone on a special table that includes a hole to allow the designated breast to dangle therethrough. The breast is compressed between two mammography plates, which stabilizes the breast to be biopsied and allows the digital mammograms to be taken. At least two images are taken 30 degrees apart to obtain stereotactic views. The x, y and z coordinates targeting the lesion are calculated by a computer. The physician then aligns a special mechanical stage mounted under the table that places the biopsy device into the breast to obtain the sample or samples. There are believed to be three methods available to biopsy lesions using a stereotactic table: (1) fine needle aspiration, (2) core needle biopsy and (3) vacuum-assisted core needle biopsy.
Fine needle aspiration uses a small gauge needle, usually 20 to 25 gauge, to aspirate a small sample of cells from the lesion or suspicious area. The sample is smeared onto slides that are stained and examined by a cytopathologist. In this technique, individual cells in the smears are examined, and tissue architecture or histology is generally not preserved. Fine needle aspiration is also very dependent upon the skill and experience of the operator and can result in a high non-diagnostic rate (up to about 83%), due to inadequate sample collection or preparation.
Core needle biopsy uses a larger size needle, usually 14 gauge to sample the lesion. Tissue architecture and histology are preserved with this method. A side-cutting device, consisting of an inner trough with an outer cutting cannula is attached to a spring-loaded device for a rapid semi-automated firing action. After the lesion is localized, local anaesthetic is instilled and a small incision is made in the skin with a scalpel. The device enters the breast and the needle tip is guided into the breast up to the targeted lesion. The device is fired. First, the inner cannula containing the trough rapidly penetrates the lesion. Immediately following this, the outer cutting cannula rapidly advances over the inner cannula cutting a sample of tissue off in the trough. The whole device is then removed and the sample retrieved. Multiple penetrations of the core needle through the breast and into the lesion are required to obtain an adequate sampling of the lesion. Over 10 samples have been recommended by some.
The vacuum-assisted breast biopsy system is a larger semi-automated side-cutting device. It is usually 11 gauge in diameter and is more sophisticated than the core needle biopsy device. Multiple large samples can be obtained from the lesion without having to reinsert the needle each time. A vacuum is added to suck the tissue into the trough. The rapid firing action of the spring-loaded core needle device is replaced with an oscillating outer cannula that cuts the breast tissue off in the trough. The physician controls the speed at which the outer cannula advances over the trough and can rotate the alignment of the trough in a clockwise fashion to obtain multiple samples.
If a fine needle aspirate, needle core biopsy or vacuum-assisted biopsy shows malignancy or a specific benign diagnosis of atypical hyperplasia, then the patient needs to undergo another procedure, the traditional needle-localized breast biopsy, to fully excise the area with an adequate margin of normal breast tissue. Sometimes the vacuum-assisted device removes the whole targeted lesion. If this occurs, a small titanium clip should be placed in the biopsy field. This clip marks the area if a needle-localized breast biopsy is subsequently required for the previously mentioned reasons.
Another method of biopsying the suspicious lesion utilizes a large end-cutting core device measuring 0.5 cm to 2.0 cm in diameter. This also uses the stereotactic table for stabilization and localization. After the lesion coordinates are calculated and local anesthesia instilled, an incision large enough is permit entry of the bore is made at the entry site with a scalpel. The breast tissue is cored down to and past the lesion. Once the specimen is retrieved, the patient is turned onto her back and the surgeon cauterizes bleeding vessels under direct vision. The incision, measuring 0.5 to larger than 2.0 cm is sutured closed.
The stereotactic table requires awkward positioning of the patient and may be extremely uncomfortable. The woman must lie prone during the entire procedure, which may be impossible for some patients. In addition, the lesion to be biopsied must be in the center working area of the mammography plates. This may be extremely difficult and uncomfortable for the patient if the lesion is very posterior near the chest wall or high towards the axilla.
The woman is subjected to increased radiation exposure as multiple radiographs are required throughout the course of the procedure to: (1) confirm that the lesion is within the working area of the mammography plates, (2) obtain the stereotactic coordinates (at least two views), (3) verify the positioning of the biopsy needle prior to obtaining tissue, and (4) verify that the lesion was indeed sampled. If any difficulty is encountered during the procedure, additional radiographic exposures are required to verify correction of the problem.
Using the core needle biopsy or vacuum-assisted device, bleeding is controlled only by manual pressure. Bleeding is generally not an issue with fine needle aspiration, but is a legitimate complication of the former two methods. Ecchymoses, breast edema and hematomas can occur. This causes increased post-procedural pain and delays healing. Rarely, the patient may require an emergency operation to control and evacuate a tense hematoma.
Another major concern is the possibility of tumor dissemination. The core needle biopsy and vacuum-assisted devices both cut into the tumor and carve out multiple samples for examination. While cutting into the tumor, cancerous cells may be dislodged. Cutting across blood vessels at the same time may allow the freed cancerous cells access to the blood stream, thus possibly seeding the tumor beyond its original locus. The long-term consequences of tumor seeding with the risk of bloodborne metastases are unknown at this time, as the techniques are relatively new. However, documented instances of cancerous cells seeding locally into needle tracks exist. There are numerous reports of metastases growing in needle tracks from previous biopsies of a cancerous mass. Most of these are from lung or liver cancers. However, at least one case of mucinous carcinoma of the breast growing in a needle track has been reported. The long-term consequences of neoplasm seeding into needle tracks are currently unknown, again because the techniques are relatively new. Some recommend excision of the entire needle track, including the skin entry site, during the definitive surgical procedure for a diagnosed cancer, whether it be a lumpectomy or a mastectomy. Others assume that with a lumpectomy, the post-operative radiation therapy will destroy any displaced cancer cells in the needle track. With the trend towards treating very small cancers only by excision and without a post-excision course of radiation therapy, the risk of cancer cells metastasizing and growing in needle tracks is very real.
The large core cutting device (0.5 to 2.0 cm) generally eliminates the risk of needle track seeding as it is designed to excise the lesion intact. A stereotactic table is required with the same inherent awkwardness for the patient, as discussed above. Bleeding is controlled, albeit manually, requiring that the patient wait until the end of the procedure to be turned over. Compression is used to stabilize the breast and localize the lesions. The breast, however, may be torqued and distorted between the compression plates such that when the plates are removed after the biopsy, the large core track left behind may not be straight, but actually tortuous. This can result in permanent breast deformity.
The location of the insertion site into the breast is dictated by the positioning of the breast in the machine and not by the physician. The entry site is usually away from the nipple-areolar complex and is usually located on the more exposed areas of the breast. For the fine needle aspirate, core biopsy and vacuum-assisted devices, the incision is usually very small and the scar almost unappreciable. However, in the case of the large core biopsy device (0.5 to 2.0 cm), a large incision is needed. Such a large incision often results in a non-aesthetically placed scar.
The newer conventional minimally invasive breast biopsy devices have improved in some ways the ability to diagnose mammographically detected nonpalpable lesions. These devices give the patient a choice as to how she wants the diagnosis to be made. Moreover, these devices are substantially less expensive than the older traditional needle-localized breast biopsy. They are not, however, the final solution. Due to the above-discussed problems and risks associated with compression, needle-track seeding, blood borne metastases, bleeding, radiation exposure and awkwardness of the stereotactic table, more refined devices and methods are needed to resolve these issues. Also, the conventional biopsy devices do not consider margins in their excisions and if cancer is diagnosed, the patient must undergo a needle-localized breast lumpectomy to ensure that adequate margins are removed around the cancer. Devices and methods, therefore, must address the problem of obtaining adequate margins so that a second procedure is not required. Margins, moreover, cannot be assessed while the breast is being compressed.
It is, therefore, an object of the present invention to provide devices and methods to efficiently and safely excise suspicious lesions from the breast. It is also an object of the present invention to provide devices and methods that remove the entire lesion intact with the minimum amount of normal tissue surrounding the lesion needed to provide adequate margins. It is a further object of the present invention to provide devices and methods that provide hemostasis in the breast to minimize complications of ecchymosis, hematoma formation, and breast edema. It is another object of the present invention to provide methods and devices to provide intra-tissue ultrasonic guidance to provide real time, in situ monitoring of the procedure. A still further object is to provide devices and methods that allow the physician to minimize the size of the incision though which the procedure is performed and to leave an aesthetically acceptable scar on the breast.
In accordance with the above-described objects and those that will be mentioned and will become apparent below, an embodiment of an excisional biopsy device according to the present invention comprises:
a tubular member having a window near a distal tip thereof;
a cutting tool, a distal end of the cutting tool being attached near the distal tip of the tubular member, at least a distal portion of the cutting tool being configured to selectively bow out of the window and to retract within the window; and
a tissue collection device externally attached at least to the tubular member, the tissue collection device being adapted to collect a tissue sample severed by the cutting tool as the biopsy device is rotated and the cutting tool is bowed.
According to further embodiments, the distal portion of the cutting tool may comprise a thin ribbon sharpened on a leading edge thereof. The leading edge of the thin ribbon may be serrated. The tubular member may comprise an internal guide allowing a proximal portion of the cutting tool to slide therein when a proximal end of the cutting tool is pushed in a distal direction or pulled in a proximal direction. The cutting tool may further comprise an interior lumen; and a plurality of through holes in the distal portion thereof, the through holes being in fluid communication with the interior lumen. The tissue collection device may comprise a bag within which the excised sample of tissue is collected. An opening of the bag may be at least co-extensive with the window in the tubular member. The tissue collection device may be configured to open and to close as the cutting tool is selectively bowed and retracted, respectively. The tissue collection device may comprise a bag attached to the tubular member and to a trailing edge of the distal portion of the cutting tool, the bag opening and closing as the cutting tool is bowed and retracted, respectively. An ultrasound sensor may be mounted within the distal portion of the tubular member, the ultrasound sensor being disposed within the tubular member so as to image tissue about to be cut by the cutting tool as the biopsy device is rotated. The ultrasound sensor may be electrically connected to at one or more data processing and display devices to allow either a real time or a near real time graphical representation of the tissue to be cut. The distal portion of the cutting tool may be electrically connected to an RF or other power source. The distal portion of the cutting tool may comprise a thin wire.
An invasive interventional device for soft biological tissue, according to a further embodiment of the present invention, comprises
a rotatable tubular member having a distal tip adapted to penetrate the tissue;
a work element disposed near the distal tip of the tubular member, the work element acting upon the tissue coming into contact therewith as the tubular member rotates;
an ultrasound transducer disposed near the distal tip of the tubular member and away from the work element, so that the transducer sweeps a plane within the tissue ahead of the work element as the tubular member rotates; and
means for controlling an operation of the work element based upon information gathered from the ultrasound transducer.
According to still further embodiments, the ultrasound transducer may be tuned within a range from about 7.5 MHz to about 20 MHz. The ultrasound transducer may be disposed within the tubular member at an angle xcex1 relative to the work element, the angle xcex1 being no smaller than that necessary to effectively control the operation of the work element in response to the information gathered from the transducer as the tubular member rotates. The angle xcex1 is preferably less than about 180 degrees. The work element may comprise at least one device selected from the group consisting of: an abrasive device, a reciprocating cutting device, a bowing cutting device, an electrosurgical device, a laser device and a vibrating device. The ultrasonic transducer may be connected to at least one data processing and display device to allow an operator of the device to ascertain a structure of the tissue and to control the operation of the work element before the tissue comes into contact with the work element as the device rotates. The work element may comprise a cutting tool, a distal end of the cutting tool being attached near the distal tip of the tubular member, at least a distal portion of the cutting tool being configured to selectively bow out of a window in the tubular member and to retract within the window. The controlling means may include means for selectively bowing and retracting the cutting tool.
According to yet another embodiment, an excisional biopsy method for soft tissue, according to the present invention, comprises the steps of:
inserting a generally tubular member into the tissue, the tubular member including a cutting tool adapted to selectively bow away from the tubular member and an external tissue collection device near a distal tip of the tubular member;
rotating the tubular member;
selectively varying a degree of bowing of the cutting tool;
collecting tissue severed by the cutting tool in the tissue collection device; and
retracting the tubular member from the soft tissue.
The rotating step may be carried out by manually rotating the tubular member. The tubular member may further include an imaging transducer and the method may further include the steps of displaying information received from the transducer on a display device; and varying the degree of bowing of the cutting tool based upon the displayed information from the imaging transducer. The cutting tool may comprise an electrosurgical blade and the method may further comprise the step of varying the power (for example, RF power) applied to the electrosurgical blade based upon information received from the transducer. A step of stabilizing the soft tissue in an uncompressed state prior to the inserting step may also be carried out. A step of controlling the cutting tool to assume a non-extended state may be carried out prior to the inserting step and before the retraction step. The tissue collection device assumes a closed configuration when the cutting tool assumes the non-extended state. The extension of the cutting tool may be controlled by selectively and manually pushing and retracting a proximal end of the cutting tool in the distal and proximal directions, respectively. The cutting tool may comprise an interior lumen and a plurality of through holes in fluid communication therewith, and the method may further comprise the step of delivering at least one fluid to the tissue via the plurality of through holes.
The present invention may also be viewed as an imaging and treatment method for soft tissue, comprising the steps of:
inserting a tubular member into the soft tissue, the tubular member including an ultrasonic transducer mounted near a distal end of the tubular member;
rotating the tubular member within the soft tissue;
displaying an output of the ultrasonic transducer on a display device; and
acting upon the soft tissue based upon the displayed output.
According to further preferred embodiments, the ultrasonic transducer may be tuned to within a frequency range of between about 7.5 MHz to about 20 MHz. The acting step may include a step of severing a selectively variable volume of soft tissue from a main tissue mass. A step of collecting the severed volume of tissue in a tissue collection device mounted externally to the tubular member may also be carried out.
According to a further embodiment, an excisional biopsy device, according to the present invention, comprises:
a tubular member having a first and a second window near a distal tip thereof;
a cutting tool configured to selectively bow out of the first window and to retract within the first window; and
a removable transducer core, the transducer core including an active transducer element configured to face out of the second window when the removable transducer core is fitted within the tubular member.
The removable core may be adapted to snap fit within the tubular member. The active transducer element may, for example, include an ultrasound transducer. The removable transducer core may include a tapered distal tip configured to readily penetrate soft tissue. An external tissue collection device may be attached to the cutting tool and/or to the tubular member. The tubular member may further comprise a recessed section adjacent a trailing edge of the cutting tool, the recessed section being adapted to receive the external tissue collection device. An expandable sheath may also be included, the expandable sheath being adapted to receive the removable transducer core and the tubular member.
The present invention may also be viewed as a method of excising a lesion from soft biological tissue using an excisional biopsy system including a generally tubular member having a cutting tool, a removable transducer core adapted to fit within the tubular member and an expandable sheath, comprising the steps of:
fitting the transducer core through the expandable sheath,
inserting the transducer and sheath though an incision in the tissue;
imaging a target site within the tissue by energizing the transducer core,
removing the transducer core from sheath while leaving the sheath in place within the tissue;
securing the core within the generally tubular member so the core faces outwardly from the tubular member;
sliding the tubular member through the expandable sheath until the cutting tool is positioned adjacent the lesion;
cutting the lesion with the cutting tool; and
retracting at least the tubular member from the incision.
A step of stabilizing the breast in one of an uncompressed and a slightly expanded state prior to the inserting step may also be carried out. The sheath may remain within the tissue after the retracting step and the method may further comprise the step of re-inserting the transducer core within the sheath and imaging the target site to insure that the lesion has been excised. A step of collecting the cut lesion within an external tissue collection device secured to the tubular member may also be carried out. Both the tubular member and the sheath may be retracted from the incision.
The present invention may also be viewed as an excisional biopsy device, comprising:
a single use disposable tubular member having a window near a distal tip thereof, the tubular member including a cutting tool, a distal end of the cutting tool being attached near the distal tip of the tubular member, at least a distal portion of the cutting tool being configured to selectively bow out of the window and to retract within the window; and
a single use disposable tissue collection device externally attached at least to the tubular member, the tissue collection device collecting tissue severed by the cutting tool as the biopsy device is rotated and the cutting tool is bowed.
In yet another embodiment, the present invention is an excisional biopsy device, comprising:
a single use disposable tubular member having a first and a second window near a distal tip thereof, the tubular member including a cutting tool configured to selectively bow out of the first window and to retract within the first window; and
a removable transducer core, the transducer core including an active transducer element configured to face out of the second window when the removable transducer core is fitted within the tubular member.